Rapid, simple and sensitive screening of foodborne pathogens is of great significance to ensure food safety. In this study, an aptamer-functionalized polydiacetylene (Apta-PDA) biosensor was developed for the detection of E. coli O157:H7, S. typhimurium or V. parahaemolyticus. First, aptamers responding to the target bacteria were modified on the surface of magnetic beads by covalent binding to form MBs-oligonucleotide conjugates for bacterial enrichment. Then, an Apta-PDA biosensor was obtained by connecting the aptamers to the PDA nanovesicles using the carbodiimide method. Molecular recognition occurred in the presence of the target bacteria, whereby the aptamer folded into a sequence-defined unique structure, resulting in an MBs-Apta/bacteria/Apta-PDA sandwich structure. Due to the optical properties of PDA, the blue-red transition of the detection system could be observed by the naked eye and quantified by the colorimetric response percentage (CR%). Under optimized conditions, the detection limits of E. coli O157:H7, S. typhimurium and V. parahaemolyticus were 39, 60 and 60 CFU/ml, respectively, with a selectivity of 100% and a reaction time of 30 min. Compared with the gold standard method, the accuracy of the three target bacteria detection reached 98%, 97.5% and 97%, respectively, and the sensitivity and specificity were both greater than 90%. The entire detection process was rapid and easy to execute without any special equipment, making this technology particularly suitable for resource-poor laboratories or regions.

中文翻译：

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用于检测三种食源性病原体的适体功能化聚二乙炔生物传感器。

快速、简便、灵敏的食源性致病菌筛查对于保障食品安全具有重要意义。在本研究中，开发了一种适体功能化聚二乙炔（Apta-PDA）生物传感器，用于检测大肠杆菌O157:H7、鼠伤寒沙门氏菌或副溶血性弧菌。首先，通过共价结合在磁珠表面修饰对目标细菌有反应的适体，形成MBs-寡核苷酸缀合物，用于细菌富集。然后，利用碳二亚胺方法将适配体连接到PDA纳米囊泡上，得到Apta-PDA生物传感器。分子识别发生在目标细菌存在的情况下，从而适体折叠成序列定义的独特结构，形成MBs-Apta/细菌/Apta-PDA 三明治结构。由于PDA的光学特性，检测系统的蓝红色转变可以通过肉眼观察到，并通过比色响应百分比（CR%）进行量化。优化条件下，大肠杆菌O157:H7、鼠伤寒沙门氏菌和副溶血弧菌的检出限分别为39、60和60 CFU/ml，选择性为100%，反应时间为30 min。与金标准方法相比，三种目标菌检测准确率分别达到98%、97.5%和97%，灵敏度和特异性均大于90%。整个检测过程快速且易于执行，无需任何特殊设备，使得该技术特别适合资源匮乏的实验室或地区。